Process of making polyvinylalcohol fibers of improved dyeability



Uited PROCESS OF MAKING POLYVINYLALCQHOL FIBERS F ROVED DYEABILITY Kanji Matsubayashi and Qsamu Fukushirna, Kurashiki City, Japan, assignors of three-fourths to Kuraslriki Rayon Co., Ltd., Okayama, Japan, a corporation of Japan, and one-fourth to Air Reduction Company intxfnporated, New York, N.Y., a corporation of New ork No Drawing. Filed May 9, 1960, Ser. No. 27,504 Claims priority, application Japan May 11, 1959 6 Claims. (Cl. 260-2.).4)

This invention relates to a process of producing fibers of polyvinyl alcohol and polyvinyl alcohol derivatives and is more particularly concerned with a process of forming such fibers which are characterized by desirable properties.

As described in U.S. patent application Ser. No. 856,334, filed December 1, 1959, now Patent No. 3,007,228, the dyeability of polyvinylalcohol fibers can be markedly increased by spinning the fibers from a mixture of an emulsified polymer formed from basic monomers and a water solution of polyvinylalcohol. When fibers spun from such a mixture are subjected to benzalization, fibers can be obtained which have excellent elastic recovcry and dyeability without showing any significant drop in dyeabsorption. This is substantially different from the results obtained by mixed spinning of water-soluble polymers containing basic nitrogen as heretofore practiced.

It is an object of this invention to provide a process for producing fibers of polyvinylalcohol and polyvinylalcohol derivatives having high hot-water resistance and heat-resistance and desirable mechanical properties at least equal to fibers produced solely from polyvinylalcohol, yet characterized by a particularly high dyeability.

In accordance with this invention, spinning of fibers is effected from a spinning fluid prepared by dispersing in a water solution of polyvinylalcohol an emulsion or fine powder of a water-insoluble poly-condensation product containing basic nitrogen.

We have studied extensively methods of manufacturing emulsions or fine powders of polymers in a search for those which would exhibit desirable effects similar to tlrose mentioned above, and we have succeeded in obtaining basic nitrogen-containing and water-insoluble poly-condensation products in emulsion or fine particles of a type which produces the desired results in combination with polyvinylalcohol and which produce spinning solutions which are readily spun without difficulty.

In accordance with the present invention, it has bee found that the desired objective can easily and economically be achieved even in the case when spinning is effected from a spinning fluid in which the emulsion or fine particles of such poly-condensation products is mixed with and dispersed in a water solution of polyvinyl alcohol, and a particularly marked increase in dyeability after benzalization can be effected.

As described in said application Ser. No. 856,334, now Patent No. 3,007,228, the particle size of the so-called emulsified polymer contained in the spinning fluid which is entirely trouble-free for the spinning operation, and also in the ultimate spun yarn, is normally below 0.1 u, whereas it is possible by the present invention to obtainvarious solid particle sizes ranging from 0.1a to 10 11. in diameter. We have also found that in the case of the present invention, the larger the particle size, the greater will be the increase in dyeability after the benzalization step. We have further discovered that if the fiber which contains such solid particles is subjected to hot-stretching, which is effective to increase hot-water resistance, tensile strength, and elasticity, the fiber not only retains its dye- Patented Sept. 11, 1962 ability without any decrease, but it also shows an increase in dyeability in direct proportion to the extent of hotstretclring, in contrast to ordinary vinylon or conventional mixed yarn containing water-soluble polymer or condensation product which have heretofore been proposed. The reason for this behavior is not entirely understood, but when the surface of such fibers is electron-microscopically examined, crevices or cracks are seen to exist to a significant extent along solid particles. On the basis of the finding, it is presumed that, in the case of such solid particles, the larger the size of the particles, the less the particles are affected by the polyvinylalcohol molecule or its benzalized portion, with the result that the dyestuif can more easily permeate the fibers. In any case, since there is an existing need for polyvinyl alcohol or vinylon fibers having excellent elastic restitution and dyeability, this invention is of substantial significance since it makes it possible to achieve this objective and to provide the desired fibers conveniently and economically.

However, when the diameter of the particles is too large, broken or nappy yarns occur with greater frequency, with subsequent deterioration of the mechanical properties of the fiber. Hence, it is important to restrict the size of the particles to below 30,u.

In accordance with the present invention, the amount of basic nitrogen in the poly-condensation product is over 0.2%, and the percentage of poly-condensation product to poly-vinyl alcohol in the spinning solution is 0.052% calculated on the amount of basic nitrogen present.

With this admixture of polyvinylalcohol and poly-condensation product, a significant increase in the dyeability of the resultant fibers is noted with direct cotton dyes and acid wool dyes, while any drop in mechanical properties such as hot-water resistance and heat-resistance is insignificant.

In carrying out the condensation reaction to obtain the emulsion or fine powder of the poly-condensation product suitable for use in accordance with the invention, it is desirable to employ high-speed agitation, or to add any of the various known surface active agents or protective colloids to the solution. As surface active agents, various anionic, non-ionic, and cationic surface active agents are suitably used, but inasmuch as an anionic surface active agent may occasionally tend to coagulate solid particles by forming a bond with basic nitrogen, it is preferred to use a non-ionic surface active agent such as polyoxyethylene-dodecyl ether, or a cationic surface active agent such as dodecyltrimethylammonium chloride. As protective colloids, water-soluble polymers such as gelatin, polyvinylpyrrolidone, and the like are suitably used.

To form a stable dispersion of the above-described solid polymer particles in a water solution of polyvinylalcohol, various procedures may be employed. Thus when the poly-condensation product is in the form of an emulsion, the emulsion may be directly mixed with a water solution of polyvinylalcohol, or it may be mixed with polyvinylalcohol powder and water may then be added to dissolve the powder. Alternatively, the emulsion may be heated, and polyvinylalcohol powder or moist polyvinylalcohol powder may be slowly added and dissolved in the emulsion. When the poly-condensation product particles are in the form of a fine powder, the powder particles may be mixed with polyvinylalcohol powder and water added to dissolve the powder mixture or the poly-condensation product particles may be mixed with a small amount of water or a water solution of polyvinylalcohol, and the paste of fine powder thus obtained may be mixed with polyvinylalcohol. It will be understood, however, that various other procedures may be used. As mentioned, various surface active agents, gelatin polyviny-lpyrrolidone, and various other types of polymers may be added as protective colloids.

aosavsc The fiber spun by the method of this invention may be subjected to thermal elongation, heat-treatment and insolubilization treatments in the same manner as fibers formed solely from ordinary polyvinylalcohol. For effecting insolubilization treatments there may be employed acetalization by means of aldehydes such as formaldehyde, acetaldehyde, chloracetaldehyde, butylaldehyde, nonylaldehyde, benzaldehyde, monochlorbenzaldehyde, l-naphthaldehyde, glyoxal, malonaldehyde, glutaraldehyde, terephthalaldehyde, and the like. The fibers may also be subjected to treatments with inorganic reagents such as titanation, and chroming. Various other known insolubilization treatments may also be employed.

It is also preferable to carry out spinning by means of the spinning fluid prepared by dispersing an emulsion or a fine powder of the poly-condensation product with polyvinylalcohol by the method of this invention, with the addition of various types of water-soluble polymers such as soluble starch, polyvinylpyrrolidone, aminoacetalizated polyvinylalcohol, various kinds of pigments such as titanium oxide, and acids, alkalis, and salts such as sodium sulfate, and the like. Accordingly, it is possible to simultaneously effect improvements in the transparency and in the form of the cross-section of the fibers particularly when the fibers are formed by wet spinning.

The water-insoluble poly-condensation products containing basic nitrogen employed in the method of this invention include formaldehyde poly-condensation products, containing basic nitrogen, or their amine treated derivatives containing basic nitrogen, or amine treated derivatives of formaldehyde poly-condensation products containing no basic nitrogen, such as melamine-formaldehyde resin, amine-treated melamine-formaldehyde resin, aminetreated dicyandiamide-formaldehyde resin, amine-treated urea or thiourca-formaldehyde resin, amine-treated phenol formaldehyde resin, amine-treated acetone-formaldehyde resin, melamine-guanidine-formaldehyde resin, urea or thioureaguanidine-formaldehyde resin, which are composed of two or more compounds and each consists of one or more compounds containing basic nitrogen. These amine-treated derivatives can easily be produced by using mineral acid salts, e.g. the hydrochlorides, of primary or secondary amines as catalysts at the time poly-condensation is carried out or by causing primary or secondary amines, and in some cases, formaldehyde, to react on such poly-condensation products. Insoluble three-dimensional poly-condensation products composed of polyamines derived from ammonia or ethylenediamine and epichlorohydrin or triethanolamine, or methylolated melamine and epichlorohydrin, or poly-condensation products of triethanolamine and phthalic acid, and emulsions and fine powders of various other types of poly-condensation products can also be suitably used.

The invention will be further understood from the following specific examples of practical application. However, it will be understood that these examples are not to be construed as limiting the scope of the present invention in any manner. In these examples, all parts are by weight, unless otherwise indicated.

Ex'ample 1 An aqueous solution (100 g.) composed of 12.5 g. of an 80% water solution of Sumitex Resin M-3 (methylolated melamine), 2 g. of polyoxyethy-lenedodecyl ether, and 0.1 cc. of concentrated hydrochloric acid was vigorously agitated at a temperature of 60 C., the solution becoming gradually turbid and white in color. After 6 hours, the solution was filtered through cotton cloth to remove the small amount of precipitate which had formed, and an emulsion containing 8.5 g. of the poly-condensation product was obtained. The dispersed solid particles of this emulsion did not dissolve even when heated in an acidic aqueous solution, but exhibited dyeability with Acid Brilliant Scarlet 3R, acid dye. When examined with an op tical microscope, the particles could hardly be seen.

4. However, electron-microscopic observation showed that the particle size was, for the most part, about 0.31;.

To the emulsion containing the insoluble melamineformaldehyde poly-condensation product (6 g.) thus obtained, 54 g. of polyvinalcohol was added, and the mixture diluted with water to form a spinning fluid having a 12% polymer concentration. The spinning fluid was then wet-spun into a sodium sulfate coagulating bath. The resultant fibers were 100% stretched at 230 C. for 30 sec., and the fibers were heat-treated at 235 C. for 30 sec. at a fixed yarn length. Some of the fibers were formalized with an aqueous solution containing formaldehyde (5%), sulfuric acid (15%) and sodium sulfate (15%), and the remaining fibers were benzalized with an aqueous solution containing benzaldehyde (2% sulfuric acid (10%) and methanol (40% The nitrogen content was 2.76% after heat-treatment, and 2.53% after formalization or benzalization. The fibers were then dyed with Acid Brilliant Scarlet 3R (2%) and sulfuric acid (2%) (the quantities being by weight based on the fiber dyed), at C. for one hour. All the specimens, namely the heat-treated and formalized, and the heat-treated and benzalized fibers, exhibited very good dyeability.

Example 2 A water solution (1 kg.) containing trimethylol-melamine (100 g.), 50 g. of a 40% water solution of SA- 40 (dodecyltrimethylammonium chloride) and 1 cc. of concentrated hydrochloric acid was agitated at 60 C. for 3 hours. The small amount of precipitate which formed was separated by filtering, and 7.5 g. of dimethylamine was added to the filtrate. After stirring at 60 C. for 3 hours, unreacted substances were removed by dialyzing in running water. An emulsion having a solids concentration of 4.6% and weighing 1.3 kg. was obtained. When examined by an optical microscope, a large number of particles of a size of about 5m were observed. This emulsion was added in the amount of 10% to a polyvinylalcohol solution to form a spinning fluid having a polymer concentration of 35%. This spinning fluid was subjected to dry-spinning by forcing the fluid out into the air through a spinning nozzle having 20 apertures each of 0.3 mm. diameter. The fibers produced were then continuously stretched by 500% at 220 C., and shrunk or relaxed by 20% at 225 C. Portions of the heat-treated fibers were formalized (sample 1) or benzalized (sample 2) as described in Example 1. The degree of acetalization of the two fiber specimens was 37.5% in the case of the formalized fibers (sample 1) and 27.0% in the case of the benzalized fibers (sample 2). The rate of shrinkage when treated in water at 100 C. was 2.0% for sample 1, and 5.1% for sample 2. The dry thermal softening point was 220 C. for sample 1 and 207 C. for sample 2. The fiber strength was 4.1 g./denier for sample 1 and 3.2 g./denier for sample 2, equal to that of ordinary formal polyvinyl alcohol. Thus the various physical properties were sulficient for practical use. Elasticity at a rate of stretch of 3% was 56% for sample 1 and 78% for sample 2, indieating a better result in the case of the benzalized fibers. When these fibers were dyed with an acid dye under the conditions described in Example 1, all the dyestulf was perfectly absorbed. When these fibers were dyed with Nippon Fast Violet BB Con., a direct dye, (2%) and sodium sulfate (10%) (the weight values being based on the fiber dyed) at C. for 2 hours, sample 1 absorbed 93% of the dye, and sample 2 absorbed 75% of the dye, a deep dyed color being obtained in both cases.

Example 3 The emulsified particles obtained by stirring a water solution containing 50 g. of dimethylol urea, 20 g. of guanidine hydrochloride and 25 g. of a 40% water solution of SA40 (dodecyltrimethylammoniumchloride) at 50 C. for 10 hours, had a significant dyeability with respect to acid dyes.

Emulsion in the amount of 5% was mixed with polyvinyl alcohol to form a spinning fluid as in Example 1 and wet-spinning of the resulting spinning fluid was effected as described in Example 1. The resultant fibers were divided into samples 3, 4, 5 and 6. Sample 3 was heat-treated at a constant yarn length, sample 4 was heattreated at a constant yarn length after hot-stretching by 50%, sample 5 was beat-treated at a constant yarn length after 100% hot-stretching and sample 6 was heat-treated by 20% hot-shrinking after 100% hot-stretching. All of the samples were 24-26% benzalized. Various properties of these samples are set forth in the following table. The samples which had been subjected to hot-stretching displayed a marked increase in dyeability.

Example 4 Trimethylolmelamine (32.4 g.), epichlorohydrin (41.7 g.) and caustic soda (18.0 g.) were dissolved and mixed in water (162 cc.). The solution thus obtained was stirred at 70 C. for 2 hours, 3 g. of dimethylamine were added, and agitation was continued for a further 2 hours. After the reaction was completed, the solution was heated at 100 C., and was vigorously agitated from time to time. The reaction product was concentrated to 100 cc. by distillation. The concentrate contained fine particles of the condensation product having particle sizes of less than 5;, and NaCl. The NaCl was removed by filtration. This condensation product was mixed with polyvinyl alcohol as described in Example 1 and wet-spinning, hot-stretching, and heat-treatment were carried out as in Example 1. Some of the treated fibers were formalized and the remaining fibers were benzalized.

Both samples exhibited very good dyeability toward acid and direct cotton dyes. When observed by an optical microscope, it was noted that the fine particles of the poly-condensation product were heavily dyed with color.

The surface-active or dispersing agents and protective colloids which are suitably employed are, in addition to those mentioned above, any of the many dispersing agents and protective colloids known to those skilled in the art of making emulsions or dispersions of polymers.

It will therefore be understood that, unless otherwise indicated, conventional operations and conventional apparatus are employed in carrying out the process of this invention including conventional mixing and emulsifying units. Similarly, conventional dyeing techniques and apparatus are suitably employed upon the fibers produced by the process of this invention. The conditions and the relative relationships set forth in the examples are those preferred in carrying out the process of the invention but it will be understood that other conditions and relationships may be used within the scope of the invention.

The spinning fluids produced in accordance with the present invention are particularly suitable for the spinning of fibers in accordance with known processes used in the spinning of polyvinylalcohol and polyvinylalcohol derivatives, particularly the so-called wet-spinning techniques as described, for example, in Cline et a1. U.S. Patent 2,610,360 and Osugi et a1. Patent No. 2,906,594. An especially preferred spinning technique is described in co- 6 pending application Serial No. 336,166 of Tomonari et al., filed February 10, 1953, and now Patent No. 2,988,802.

After formation of the fibers by Wet spinning the filaments can be further treated by stretching, heat treating, acetalization, and the like to produce fibers with desirable and outstanding properties, using known techniques as described in said patents.

It will also be understood that various changes and modifications in addition to those indicated above may be made in the embodiments herein described without departing from the scope of the invention as defined in the appended claims. It is intended, therefore, that all matter contained in the foregoing description shall be interpreted as illustrative only and not as limitative of the invention.

We claim:

1. An aqueous polyvinylalcohol spinning fluid adapted to be spun to form polyvinyl alcohol fibers of increased dyeability, said spinning fluid containing a major proportion of polyvinyl alcohol dissolved therein and having dispersed therein a minor proportion of finely-divided particles of a water-insoluble formaldehyde poly-consensation product containing basic nitrogen, said poly-condensation product being present in the amount of at least 0.05 percent in relation to the polyvinylalcohol calculated on the amount of basic nitrogen present in said product.

2. An aqueous polyvinylalcohol spinning fluid adapted to be spun to form polyvinylalcohol fibers of increased dyeability, said spinning fluid containing a major proportion of polyvinylalcohol dissolved therein and having dispersed therein a minor proportion of finely-divided particles of a Water-insoluble amine-treated formaldehyde poly-condensation product containing basic nitrogen, said poly-condensation product being present in the amount of at least 0.05 percent in relation to the polyvinylalcohol calculated on the amount of basic nitrogen present in said product.

3. An aqueous polyvinylalcohol spinning fluid adapted to be spun to form polyvinyl alcohol fibers of increased dyeability, said spinning fluid containing a major propor tion of polyvinyl alcohol dissolved therein and having dispersed therein a minor proportion of finely-divided particles of a water-insoluble formaldehyde poly-condensation product containing basic nitrogen, said polycondensation product being present in the amount of at least 0.05 percent in relation to the polyvinylalcohol calculated on the amount of basic nitrogen present in said product, said poly-condensation product being a polycondensation product of formaldehyde and at least one member selected from the group consisting of melamine, dicyandiamide, urea, thiourea and guanidine, and the amine-treated derivatives thereof.

4. In the manufacture of polyvinylalcohol fibers exhibiting increased dyeability, the improvement which comprises spinning the aqueous polyvinylalcohol spinning fluid defined in claim 1 to form fibers therefrom.

5. In the manufacture of polyvinylalcohol fibers exhibiting increased dyeability, the improvement which comprises spinning the aqueous polyvinylalcohol spinning fluid defined in claim 2 to form fibers therefrom.

6. In the manufacture of polyvinylalcohol fibers eX- hibiting increased dyeability, the improvement which comprises spinning the aqueous polyvinylalcohol spinning fluid defined in claim 3 to form fibers therefrom.

References Cited in the file of this patent UNITED STATES PATENTS 

1. AN AQUEOUS POLYVINYLALCOHOL SPINNING FLUID ADAPTED TO BE SPUN TO FORM POLYVINYL ALCOHOL FIBERS OF INCREASED DYEABILITY, SAID SPINNING FLUID CONTAINING A MAJOR PROPORTION OF POLYVINYL ALCOHOL DISSOLVED THEREIN AND HAVING DISPERSED THEREIN A MINOR PROPORTION OF FINELY-DIVIDED PARTICLES OF A WATER-SOLUBLE FORMALDEHYDE POLY-CONSENSATION PRODUCT CONTAINING BASIC NITROGEN, SAID POLY-CON DENSATION PRODUCT BEING PRESENT IN THE AMOUNT OF AT LEAST 0.05 PERCENT IN RELATION TO THE POLYVINYLALCOHOL CALCULATED ON THE AMOUNT OF BASIC NITROGEN PRESENT IN SAID PRODUCT. 